Final answer:
The adaptation that does not help an animal move through the water is the streamlined layer of blubber, as it is primarily for thermal insulation, not for maneuverability.
Step-by-step explanation:
Organisms that live in aquatic environments such as freshwater and marine biomes have developed unique adaptations to aid in their survival and movement through water. However, not all adaptations they have evolved are related to movement. Looking at the options provided, streamlined layer of blubber and flippers and flattened, almost furless body, we can infer that the adaptation that does not help an animal move through the water is the streamlined layer of blubber. While a streamlined body shape does reduce drag and aids in movement, the layer of blubber itself is primarily for insulation against cold temperatures and not specifically for maneuverability in water.
Marine and freshwater animals exhibit various other adaptations for aquatic life. For example, fish have gills to extract oxygen from water, a stream-lined body to efficiently move through water, fins for propulsion and steering, and a swim bladder to control buoyancy. Unlike these adaptations, a layer of blubber is more about insulation rather than aiding in propulsion or navigation through the water.